Casper Posted February 21, 2011 Report Share Posted February 21, 2011 Problem attached. Have fun. Quote Link to comment Share on other sites More sharing options...
Disclaimer Posted February 21, 2011 Report Share Posted February 21, 2011 a) 17500*SQRT(2) = 24041.6 mphb) Assuming the center of earth is the origin (and they're asking for the equation of the orbiting satellite, not the one that flies off into space), in Cartesian coordinates, the equation of a circle is x^2+y^2=r^2, so with the earth being 4100 miles. it's x^2+y^2=4100^2.But if they want the parabola -- 4(4100)(y+4100)=-(x^2)16400y+4*4100^2=-x^216400y=-x^2-4*4100^2y = -x^2/16400-4100Valid for domain x = 0+ Quote Link to comment Share on other sites More sharing options...
ohdaho Posted February 21, 2011 Report Share Posted February 21, 2011 At a quick glance its pretty trivial orbital mechanics. I dont have my books on my so I cant reference the equations right now. Maybe later, but Im sure someone will have it up by then. Quote Link to comment Share on other sites More sharing options...
r1crusher Posted February 21, 2011 Report Share Posted February 21, 2011 Too late....ORDN's #1 nerd has answered the question. Quote Link to comment Share on other sites More sharing options...
Disclaimer Posted February 21, 2011 Report Share Posted February 21, 2011 It's going to be a long afternoon -- so I don't mind doing Casper's math homework in exchange for a small mental challenge. Quote Link to comment Share on other sites More sharing options...
Casper Posted February 21, 2011 Author Report Share Posted February 21, 2011 a) 17500*SQRT(2) = 24041.6 mph You have the equation correct, but the answer is wrong. LOL. Not quite sure what you did there. Make sure you get the square root of 2 first (1.414213562~), then multiply by 17500. The correct answer is 24748.7 MPH. b) Assuming the center of earth is the origin (and they're asking for the equation of the orbiting satellite, not the one that flies off into space), in Cartesian coordinates, the equation of a circle is x^2+y^2=r^2, so with the earth being 4100 miles. it's x^2+y^2=4100^2.But if they want the parabola -- 4(4100)(y+4100)=-(x^2)16400y+4*4100^2=-x^216400y=-x^2-4*4100^2y = -x^2/16400-4100Valid for domain x = 0+Really close. Really, really close. First, yes the center of the earth is the origin. If you look, x and y are even labeled in the image. The Vertex is (0,4100). According to the image, the graph of the parabola opens down, so p has to be negative. You know p is 4100, as it's given to you.(x-h)^2=4p(y-k)(x-0)^2=4(-4100)(y-4100)x^2=-16400y+67,240,00016400y=-x^2+67,240,000So, the correct answer for the parabolic path would be y=(-x^2/16400)+4100 where x>0. Quote Link to comment Share on other sites More sharing options...
r1crusher Posted February 21, 2011 Report Share Posted February 21, 2011 **Thread archived just to prove later on that MJ is a smarter enginerd than JRM** 1 Quote Link to comment Share on other sites More sharing options...
Disclaimer Posted February 21, 2011 Report Share Posted February 21, 2011 (edited) You have the equation correct, but the answer is wrong. LOL. Not quite sure what you did there. Make sure you get the square root of 2 first, then multiply by 17500. The correct answer is 24748.7 MPH.I plugged it into Excel like this: =17500*SQRT(2)... so? Maybe I looked at the wrong cell? I just quick plugged it into to the sheet I was working on other stuff with. I get Casper's number this time. Really close. Really, really close. First, yes the center of the earth is the origin. If you look, x and y are even labeled in the image. The Vertex is (0,4100). According to the image, the graph of the parabola opens down, so p has to be negative. You know p is 4100, as it's given to you.I remembered to put the parabola negative (-x), but I goofed when I put the vertex at -4100, hence why my original answer has a wrong sign for the intercept. Good catch.I should've caught it when I plugged the equation in here to check: http://webgraphing.com/graphing_basic.jsp, but it puts the x-axis on the bottom regardless of where your y-axis is, so I missed it. Edited February 21, 2011 by JRMMiii Quote Link to comment Share on other sites More sharing options...
Bad324 Posted February 21, 2011 Report Share Posted February 21, 2011 the answer is 25how'd i get that answer? well I looked at the temperature and thats what it is outside and its just god damn depressing 1 Quote Link to comment Share on other sites More sharing options...
Casper Posted February 21, 2011 Author Report Share Posted February 21, 2011 the answer is 25how'd i get that answer? well I looked at the temperature and thats what it is outside and its just god damn depressingIt's 34 here. Quote Link to comment Share on other sites More sharing options...
JonS Posted February 21, 2011 Report Share Posted February 21, 2011 /thread 1 Quote Link to comment Share on other sites More sharing options...
Beegreenstrings Posted February 21, 2011 Report Share Posted February 21, 2011 its rainy with a side of shitty with more of this fucking shit predicted to ruin the rest of our lives... Quote Link to comment Share on other sites More sharing options...
Zach Posted February 21, 2011 Report Share Posted February 21, 2011 42 Quote Link to comment Share on other sites More sharing options...
buxnut Posted February 21, 2011 Report Share Posted February 21, 2011 /threadyou beat me to it!!! Quote Link to comment Share on other sites More sharing options...
redbarron77 Posted February 21, 2011 Report Share Posted February 21, 2011 the answer is 25how'd i get that answer? well I looked at the temperature and thats what it is outside and its just god damn depressingit's 76 here....a bit windy...partly cloudy. Quote Link to comment Share on other sites More sharing options...
chevysoldier Posted February 22, 2011 Report Share Posted February 22, 2011 (edited) Problem attached. Have fun hurting your headblah blah blah blah blah blah You're close but still fricken wrong! blah blah blah should have blah blah and blah mmmkkay?I didn't do it wrong, the computer did. geesh Blah blah blahThis is the only thing in here that made sense to me.the answer is 25how'd i get that answer? well I looked at the temperature and thats what it is outside and its just god damn depressing. I'm gonna stay out of threads like this anymore. You all make me feel dumb. Edited February 22, 2011 by chevysoldier typo Quote Link to comment Share on other sites More sharing options...
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